Which hereditary condition may lead to mental retardation and infantile spasms without dietetic treatment?

Phenylketonuria (PKU) is a hereditary condition that occurs due to a deficiency in the enzyme phenylalanine hydroxylase, which is necessary for breaking down the amino acid phenylalanine. When individuals with PKU consume foods high in phenylalanine, it accumulates in the body and can lead to various neurological issues, including mental retardation and seizures, such as infantile spasms.

Dietetic treatment, which involves a strict, low-phenylalanine diet starting as early as possible, is crucial for preventing the severe consequences of PKU. If left untreated, the high levels of phenylalanine in the bloodstream can lead to irreversible brain damage and developmental delays, including mental retardation and seizures.

In contrast, other options listed, such as Down's Syndrome, Tay-Sach's Disease, and Sturge-Weber's Disease, involve different pathophysiological mechanisms. While these conditions can also result in developmental challenges, the direct link to dietary management and the specific risk of infantile spasms without dietary intervention is notably associated with Phenylketonuria. This emphasizes the importance of timely diagnosis and adherence to dietary restrictions in managing PKU effectively.